CONICET | Buscador de Institutos y Recursos Humanos

?Proyecto Yacaré? started in 1990 Santa Fe, Argentina, because of the reduction of wild Caiman latirostris populationsand it was implemented as management and monitoring plan. Although ranching system has a noteworthy success in termsof population recovery, there is scarce information about the estimation of population-genetic parameters. In particular,the consequence of the bottleneck phenomenon underwent by these populations has not been clearly described. In thiswork, we evaluated variability and genetic structure of broad-snouted caiman populations from Santa Fe over time, usingmicrosatellites and sequence analysis of a mitochondrial DNA fragment (CytB). Population genetic parameters werecompared among four sites and three different periods to assess the impact of management activities, and effective populationsize was estimate in order to detect bottleneck events. As a result, we observed an increase in genetic variability at nuclearlevel and low genetic variability in mitochondrial DNA lineages overtime. Variability estimates were similar among sitesin each sampling period with no or low differentiation among them; therefore, these populations are, apparently, part of thesame evolutionarily significant unit. The genetic background of each sampling site has changed overtime and populationsare apparently not stable. Taking into account the expected heterozygosity and effective population size values, it can beassumed that bottleneck events indeed have existed in the past. Our results seem to suggest those management activitiesthat increased the population size, also have contributed to maintain or increase genetic viability of the species. However,the information is still incomplete, and regular monitoring should continue in order to arrive at solid conclusions.